The sub-contractor, in his mid-40s, was airlifted to the Broomfield Hospital, Chelmsford, with serious injuries after coming into contact with a high-voltage overhead cable while working on land at LF Papworth Ltd, off Church Road, Felmingham.

A Papworth family spokesman has expressed their sympathy for the victim, who has not been named.

UK Power Networks were called at 2.10pm yesterday to a high-voltage overhead electricity line which had been brought down by a vehicle. Power had been isolated and an engineer had been on site within 15 minutes, said a spokesman.

A second man was taken to the Norfolk and Norwich University Hospital by road ambulance, as a precautionary measure, with non life-threatening injuries.

The incident caused a power cut to 841 Felmingham properties and about 200 were still without electricity at 6.30pm.

Jim Papworth said inspectors from the Health and Safety Executive were carrying out an investigation.

“There is very little we can say at the moment. The whole business is feeling sympathy and hoping the gentleman concerned, who was a sub-contractor, is going to be OK,” said Mr Papworth, who was not on the farm at the time.

He confirmed that borehole drilling was under way on the land but he could not say how the accident had happened.

The vehicle involved had been on site for several months and, at the time of the accident, the business’ own health and safety officer had been present.

The man was treated and sedated at the scene for about an hour by road and East Anglian Air Ambulance crew before being airlifted.

Wendy Day, who lives in nearby Elaine Road, was walking her dog past the farm at about 5.45pm and saw men in hard hats and high-visibility jackets “on the ground looking for something” and others in a cherry picker on the back of a white vehicle.

Mrs Day said UK Power Networks had told her they would not be able to restore her electricity until the safety inspectors had finished on the site. She was brewing tea on a camping stove for herself and neighbour Christine Morter.

The Papworth family suffered their own near-tragedy in October 2010 when Jim Papworth’s son Tim, co-director of the business with his cousin Kit Papworth, fell and hit his head on concrete while changing a light bulb, suffering two bleeds on his brain. He was airlifted to Addenbrooke’s Hospital, Cambridge, and remained in a coma for five weeks.

The Papworths have since raised substantial funds for the air ambulance to thank them.

The award-winning family business provides contract arable services as well as producing potatoes, peas, oilseed rape and malting barley, as well as beef and lamb for sister businesses J and D Papworth Ltd, and Papworth Farms Ltd.

Last night, an East Anglian Air Ambulance statement said: “Anglia Two were tasked to an incident in Felmingham, near North Walsham, Norfolk, this afternoon. A man in his mid-40s had come into contact with an overhead cable.

“Captain Dave Webber flew Dr Monojit Choudhury and CCP (critical care paramedic) Mark Milsom to the scene of the incident. The patient was sedated at the scene and airlifted to the specialist burns unit at Broomfield Hospital in Essex.’’

Have you been affected by this incident? Contact alex.hurrell@archant.co.uk